Shawhan is part of a large team of researchers who operate LIGO, a set of two giant, L-shaped experiments in Louisiana marshland and Washington state forestland. The facilities each feature two 2.5-mile-long steel tubes built in perfectly straight lines that are designed to detect one of the faintest and most rare signals in the universe — gravitational waves.
According to Einstein's General Theory of Relativity, gravitational waves are sent out by any object that undergoes acceleration. The waves are so faint, however, that only those emanating from huge events — such as colliding neutron stars or two black holes smashing together — can be detected.
Even waves from these events are so faint that by the time they reach Earth, they will be recorded by a difference of timing in the instruments amounting to just 0.0000000000000000000000001th of a second.
"This is one of the hardest parts of his theory to prove because the waves we hope to see are just so incredibly weak," said Shawhan. "It's a tiny effect."
So far, the crew of scientists has no direct evidence the waves are there. But a century ago Einstein proposed their existence, and so they're confident they'll prove him right. It's just a matter of when.
An instrument at the joint of the two passageways sends light beams down each arm. The light travels down the tubes and hits mirrors at the near and far ends of each tunnel and then bounces back and forth 100 times.